Agent Runtime Security Benchmark
Nexus Shield Proof Center metrics are produced by a reproducible open-source harness covering parameter hijacking, intent divergence, MCP scope abuse, and multi-agent trajectory violations.
Evidence Bundle Chain
Every evaluated action produces a reproducible cryptographic evidence bundle:
- Agent Identity — who initiated the runtime session
- Requested Intent — declared user or planner objective
- Tool Call — MCP JSON-RPC method, tool name, and arguments
- Before State Hash — SHA-256 digest of pre-action system state
- After State Hash — post-action digest (or UNVERIFIED if blocked)
- Cryptographic Evidence Bundle — signed, downloadable JSON for audit
Coverage
- 500+ MCP attack scenarios — indirect injection, cross-tool exfil, privilege escalation
- MCP-SEC-SCORE (0–100) composite grade with letter bands A+ through F
- Sub-10ms runtime intercept latency (p50 / p95 / p99)
- UNVERIFIED_ACTION detection when evidence chain breaks
Reproducibility
External researchers can reproduce MCP-SEC-SCORE locally — no Nexus Shield account required:
docker run --rm ghcr.io/baturhantasdelen-sudo/harness:latest --eval-mcp # 2026 Shadow AI scorecard (Top-10 frameworks): docker run --rm ghcr.io/baturhantasdelen-sudo/harness:latest --eval-scorecard # or from source: git clone https://github.com/baturhantasdelen-sudo/harness cd harness && python scripts/run_reproducible_benchmark.py --eval-mcp
Full interactive matrix: 2026 Enterprise AI Agent Security Scorecard
Listed on corca-ai/awesome-llm-security and submitted to mcpservers.org.
MCP Tool-Hijack Security Leaderboard
Great MCP Tool-Hijack Benchmark
Live harness results from indirect prompt injection, cross-tool exfiltration, and privilege escalation scenarios across production MCP adapters.
Block Rate
100% (5/5 blocked)
Scenarios Evaluated
5
Proof Center Baseline
Meets 99.3%
| Target MCP Adapter | Attack Vectors | Vulnerabilities | Grade | Nexus Shield Status |
|---|---|---|---|---|
@modelcontextprotocol/server-fetch | SSRF · HTTP Exfiltration | 2 detected | F | Protected |
@modelcontextprotocol/server-filesystem | Path Traversal · Unauthorized Write | 3 detected | F | Protected |
github | PR Poisoning · Pipeline Hijack | 4 detected | F | Protected |
@modelcontextprotocol/server-postgres | Data-to-Tool Hijack · SQL Exfiltration | 2 detected | F | Protected |
slack + github (cross-tool) | Cross-Tool Exfiltration · Secret Enumeration | 2 detected | F | Protected |
Last updated 2026-09-21T11:24:44Z · Open-source harness: baturhantasdelen-sudo/harness